Video: Europe's battle with al-Qaida

In France, Tuesday, security agents detained seven people suspected of helping funnel Islamic militants into Iraq. In Mainz, Germany, this weekend, police arrested an alleged al-Qaida operative who is also accused of recruiting for Iraq. He is alleged to be a key al-Qaida recruiter who was living in an apartment building on a quiet street. Also arrested: a Palestinian allegedly headed to fight in Iraq.

U.S. officials tell NBC News that the recruiter, Ibrahim Mohammed Khalil, is an al-Qaida facilitator who trained in camps in Afghanistan, fought there after 9/11 and was sent back to Germany. There, both U.S. and German intelligence monitored him.

"He also had contact to the leadership of al-Qaida, including Osama bin Laden," says Kay Nehm, the German federal prosecutor working the case.

Experts say the arrest underscores al-Qaida's interest in the war in Iraq.

"It demonstrates that Europe is the central recruitment ground for al-Qaida when it comes to finding jihadists to fight in Iraq," says NBC terror analyst Roger Cressey.

Three men from a mosque in the Paris suburbs that was raided by French police died fighting in Iraq in recent months. One was a suicide bomber.

"They began by dozens, now there are hundreds," says Antoine Sfeir, an Islamic expert in France. "Not only French. Europeans from Germany, from Belgium, from Netherlands."

Even in the tiny town of Cremona, Italy, suspected terror cells provide money, fake documents and safe passage. Last year, Italian police charged five men with allegedly plotting to blow up the Milan subway and recruiting suicide bombers for Iraq.

"The same network that was recruiting fighters for bin Laden in Afghanistan is now sending militants to fight in Iraq," says Lorenzo Vidino, an Italian terrorism analyst.

And they may be getting help from radical imams, such as Sheik Omar Bakri Muhammad in London, who gives nightly Internet sermons urging young Muslims to go to Iraq.

Despite stronger anti-terror laws, experts say it isn't always easy to take down recruiting cells or to stop heated religious rhetoric that incites young men. European officials say they may not be able to do much more with inflammatory imams than deport them.